| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| HESO3 | Helxine soleirolii Req. | Soleirolia soleirolii | Urticaceae
|
| HEAL5 | Hemarthria altissima (Poir.) Stapf & C.E. Hubbard | limpograss | Poaceae
|
| HEMAR | Hemarthria R. Br. | jointgrass | Poaceae
|
| HECI9 | Hemerocallis citrina Baroni | citron day-lily | Liliaceae
|
| HEFL13 | Hemerocallis flava (L.) L. | Hemerocallis lilioasphodelus | Liliaceae
|
| HEFUK | Hemerocallis fulva (L.) L. var. kwanso Regel | Hemerocallis fulva | Liliaceae
|
| HEFU | Hemerocallis fulva (L.) L. | orange daylily | Liliaceae
|
| HEJA2 | Hemerocallis japonica (Thunb.) Thunb. 1784, non Thunb. 1794 | Hosta lancifolia | Liliaceae
|
| HELA13 | Hemerocallis lancifolia Thunb. | Hosta lancifolia | Liliaceae
|
| HELIF | Hemerocallis lilioasphodelus L. var. flava L. | Hemerocallis lilioasphodelus | Liliaceae
|
| HELI4 | Hemerocallis lilioasphodelus L. | yellow daylily | Liliaceae
|
| HEMI17 | Hemerocallis minor P. Mill. | small daylily | Liliaceae
|
| HEPL3 | Hemerocallis plantaginea Lam. | Hosta plantaginea | Liliaceae
|
| HEMER | Hemerocallis L. | daylily | Liliaceae
|
| HEGL15 | Hemiachyris glutinosa S. Schauer | Gutierrezia texana var. glutinosa | Asteraceae
|
| HETE16 | Hemiachyris texana DC. | Gutierrezia texana var. texana | Asteraceae
|
| HECA12 | Hemianthus callitrichoides Griseb. | Micranthemum umbrosum | Scrophulariaceae
|
| HEGL14 | Hemianthus glomeratus (Chapman) Pennell | Micranthemum glomeratum | Scrophulariaceae
|
| HEMI4 | Hemianthus micranthemoides Nutt. | Micranthemum micranthemoides | Scrophulariaceae
|
| HEAR7 | Hemicarpha aristulata (Coville) Smyth | Lipocarpha aristulata | Cyperaceae
|
| HEDR3 | Hemicarpha drummondii Nees | Lipocarpha drummondii | Cyperaceae
|
| HEMIA2 | Hemicarpha micrantha (Vahl) Pax var. aristulata Coville | Lipocarpha aristulata | Cyperaceae
|
| HEMID3 | Hemicarpha micrantha (Vahl) Pax var. drummondii (Nees) Friedland | Lipocarpha drummondii | Cyperaceae
|
| HEMIM3 | Hemicarpha micrantha (Vahl) Pax var. minor (Schrad.) Friedland | Lipocarpha micrantha | Cyperaceae
|
| HEMI5 | Hemicarpha micrantha (Vahl) Pax | Lipocarpha micrantha | Cyperaceae
|
| HEOC3 | Hemicarpha occidentalis Gray | Lipocarpha occidentalis | Cyperaceae
|
| HEFR5 | Hemichaena fruticosa Benth. | | Scrophulariaceae
|
| HEMIC2 | Hemichaena Benth. | hemichaena | Scrophulariaceae
|
| HEMA5 | Hemidictyum marginatum (L.) K. Presl | halfnetfern | Dryopteridaceae
|
| HEMID | Hemidictyum K. Presl | hemidictyum | Dryopteridaceae
|
| HEOC4 | Hemidiodia ocymifolia (Willd. ex Roemer & J.A. Schultes) K. Schum. | Diodia ocymifolia | Rubiaceae
|
| HERA4 | Hemieva ranunculifolia (Hook.) Raf. | Suksdorfia ranunculifolia | Saxifragaceae
|
| HEAL12 | Hemigraphis alternata (Burm. f.) T. Anders. | redivy | Acanthaceae
|
| HERE6 | Hemigraphis reptans (G. Forst.) T. Anders. ex Hemsl. | redflame | Acanthaceae
|
| HEMIG | Hemigraphis Nees | hemigraphis | Acanthaceae
|
| HEPA12 | Hemionitis palmata L. | starfern | Pteridaceae
|
| HEMIO | Hemionitis L. | hemionitis | Pteridaceae
|
| HEES | Hemitelia escuquensis Karst. | Cyathea andina | Cyatheaceae
|
| HEHO4 | Hemitelia horrida (L.) R. Br. ex Spreng. | Cnemidaria horrida | Cyatheaceae
|
| HECO6 | Hemitomes congestum Gray | coneplant | Monotropaceae
|
| HEMIT | Hemitomes Gray | coneplant | Monotropaceae
|
| HEAR4 | Hemizonia arida Keck | redrock tarweed | Asteraceae
|
| HEAU2 | Hemizonia australis (Keck) Keck | Hemizonia parryi ssp. australis | Asteraceae
|
| HECA6 | Hemizonia calyculata (Babcock & Hall) Keck | Hemizonia congesta ssp. calyculata | Asteraceae
|
| HECL | Hemizonia clementina Brandeg. | Catalina tarweed | Asteraceae
|
| HECL2 | Hemizonia clevelandii Greene | Hemizonia congesta ssp. clevelandii | Asteraceae
|
| HECOC5 | Hemizonia congesta DC. ssp. calyculata Babcock & Hall | hayfield tarweed | Asteraceae
|
| HECOC6 | Hemizonia congesta DC. ssp. clevelandii (Greene) Babcock & Hall | hayfield tarweed | Asteraceae
|
| HECOC2 | Hemizonia congesta DC. ssp. congesta | hayfield tarweed | Asteraceae
|
| HECOL2 | Hemizonia congesta DC. ssp. leucocephala (Tanowitz) Keil | hayfield tarweed | Asteraceae
|
| HECOL3 | Hemizonia congesta DC. ssp. luzulifolia (DC.) Babcock & Hall | hayfield tarweed | Asteraceae
|
| HECOT | Hemizonia congesta DC. ssp. tracyi Babcock & Hall | hayfield tarweed | Asteraceae
|
| HECOV | Hemizonia congesta DC. ssp. vernalis (Keck) Tanowitz | hayfield tarweed | Asteraceae
|
| HECO7 | Hemizonia congesta DC. | hayfield tarweed | Asteraceae
|
| HECO8 | Hemizonia conjugens Keck | Otay tarweed | Asteraceae
|
| HECOC3 | Hemizonia corymbosa (DC.) Torr. & Gray ssp. corymbosa | coastal tarweed | Asteraceae
|
| HECOM | Hemizonia corymbosa (DC.) Torr. & Gray ssp. macrocephala (Nutt.) Keck | coastal tarweed | Asteraceae
|
| HECO9 | Hemizonia corymbosa (DC.) Torr. & Gray | coastal tarweed | Asteraceae
|
| HEDO3 | Hemizonia douglasii Gray | Calycadenia villosa | Asteraceae
|
| HEFA | Hemizonia fasciculata (DC.) Torr. & Gray | clustered tarweed | Asteraceae
|
| HEFI | Hemizonia fitchii Gray | Fitch's tarweed | Asteraceae
|
| HEFL4 | Hemizonia floribunda Gray | Tecate tarweed | Asteraceae
|
| HEFR4 | Hemizonia fremontii (Gray) Gray | Calycadenia fremontii | Asteraceae
|
| HEHA | Hemizonia halliana Keck | Hall's tarweed | Asteraceae
|
| HEHI9 | Hemizonia hispida Greene | Calycadenia multiglandulosa | Asteraceae
|
| HEINF | Hemizonia increscens (Hall ex Keck) Tanowitz ssp. foliosa (Hoover) Tanowitz | grassland tarweed | Asteraceae
|
| HEINI | Hemizonia increscens (Hall ex Keck) Tanowitz ssp. increscens | grassland tarweed | Asteraceae
|
| HEINV | Hemizonia increscens (Hall ex Keck) Tanowitz ssp. villosa Tanowitz | grassland tarweed | Asteraceae
|
| HEIN5 | Hemizonia increscens (Hall ex Keck) Tanowitz | grassland tarweed | Asteraceae
|
| HEKE | Hemizonia kelloggii Greene | Kellogg's tarweed | Asteraceae
|
| HELA3 | Hemizonia laevis (Keck) Keck | Hemizonia pungens ssp. laevis | Asteraceae
|
| HELE3 | Hemizonia leucocephala Tanowitz | Hemizonia congesta ssp. leucocephala | Asteraceae
|
| HELO4 | Hemizonia lobbii Greene | threeray tarweed | Asteraceae
|
| HELU2 | Hemizonia lutescens (Greene) Keck | Hemizonia congesta ssp. congesta | Asteraceae
|
| HELUR | Hemizonia luzulifolia DC. ssp. rudis (Benth.) Keck | Hemizonia congesta ssp. luzulifolia | Asteraceae
|
| HELUT | Hemizonia luzulifolia DC. ssp. tracyi Babcock & Hall | Hemizonia congesta ssp. tracyi | Asteraceae
|
| HELUL2 | Hemizonia luzulifolia DC. var. lutescens Greene | Hemizonia congesta ssp. congesta | Asteraceae
|
| HELU3 | Hemizonia luzulifolia DC. | Hemizonia congesta ssp. luzulifolia | Asteraceae
|
| HEMI6 | Hemizonia minthornii Jepson | Santa Susana tarweed | Asteraceae
|
| HEMO5 | Hemizonia mohavensis Keck | Mojave tarweed | Asteraceae
|
| HEMO7 | Hemizonia mollis (Gray) Gray | Calycadenia mollis | Asteraceae
|
| HEMUV | Hemizonia multicaulis Hook. & Arn. ssp. vernalis Keck | Hemizonia congesta ssp. vernalis | Asteraceae
|
| HEMU | Hemizonia multicaulis Hook. & Arn. | Hemizonia congesta ssp. congesta | Asteraceae
|
| HEMUS | Hemizonia multiglandulosa (DC.) Gray var. sparsa Gray | Calycadenia fremontii | Asteraceae
|
| HEOP | Hemizonia oppositifolia Greene | Calycadenia oppositifolia | Asteraceae
|
| HEPA5 | Hemizonia pallida Keck | Kern tarweed | Asteraceae
|
| HEPAI | Hemizonia paniculata Gray ssp. increscens Hall ex Keck | Hemizonia increscens ssp. increscens | Asteraceae
|
| HEPA6 | Hemizonia paniculata Gray | San Diego tarweed | Asteraceae
|
| HEPAA2 | Hemizonia parryi Greene ssp. australis Keck | pappose tarweed | Asteraceae
|
| HEPAC | Hemizonia parryi Greene ssp. congdonii (Robins. & Greenm.) Keck | Congdon's tarweed | Asteraceae
|
| HEPAP3 | Hemizonia parryi Greene ssp. parryi | pappose tarweed | Asteraceae
|
| HEPAR2 | Hemizonia parryi Greene ssp. rudis (Greene) Keck | pappose tarweed | Asteraceae
|
| HEPA7 | Hemizonia parryi Greene | pappose tarweed | Asteraceae
|
| HEPA17 | Hemizonia pauciflora (Gray) Gray | Calycadenia pauciflora | Asteraceae
|
| HEPE2 | Hemizonia pentactis (Keck) Keck | Salinas River tarweed | Asteraceae
|
| HEPUL | Hemizonia pungens (Hook. & Arn.) Torr. & Gray ssp. laevis Keck | common tarweed | Asteraceae
|
| HEPUM | Hemizonia pungens (Hook. & Arn.) Torr. & Gray ssp. maritima (Greene) Keck | common tarweed | Asteraceae
|
| HEPUP | Hemizonia pungens (Hook. & Arn.) Torr. & Gray ssp. pungens | common tarweed | Asteraceae
|
| HEPUS2 | Hemizonia pungens (Hook. & Arn.) Torr. & Gray ssp. septentrionalis Keck | common tarweed | Asteraceae
|
| HEPUS | Hemizonia pungens (Hook. & Arn.) Torr. & Gray var. septentrionalis (Keck) Cronq. | Hemizonia pungens ssp. septentrionalis | Asteraceae
|
| HEPU5 | Hemizonia pungens (Hook. & Arn.) Torr. & Gray | common tarweed | Asteraceae
|